The A To A Of Scales. Part 3: Modes

This article has two aims. The first is to hopefully explain the correct usage of modes, and the second is to show that knowing your pentatonic minor scales can be the key to knowing all your scales/modes.
WHAT IS A MODE?
There's a lot of dispute and confusion surrounding the subject of modes, and how to use them, and I too have misunderstood them and found them hard to get to grips with. I'm not saying I have the definitive low-down on modes, but I think I can safely say what is and is not modal usage, he said worriedly.
It's all to do with making a distinction between root notes and key notes, and not grouping the modes together as a subset of a major key. That is to say that A Dorian, B Phrygian, C Lydian, D Mixolydian, E Aeolian, F# Locrian have nothing at all to do with the key of G major. They share the same notes but that's all, so grouping, and thinking of them in this way can be misleading.
If I'm playing over a G, Am, C, D progression in the key of G, and I play from A to A over the Am bit, I'm not using the Dorian mode.
When I play the Am part of the progression, I haven't changed key to A minor, and so haven't changed modes because to play in A Dorian, A must be the key note, and the key must be A minor not G major. The A note has to have the finality of the home sound for A Dorian to have the Dorian flavour.
HOW TO HEAR THE MODES
A good way to really hear the sound of a mode is to create a drum track with a bass playing a simple groove using just the key note. If you wanted to hear the sound of the Lydian mode in C, then while the bass plays a C note on a constant loop, play in C major, C, D, E, F, G, A, B, C, for about 5-10 minutes to really establish C major in your mind. Then suddenly replace the F natural with an F#. The Lydian sound will smack you in the face with it's interestingness. Do the same to appreciate the Mixolydian. Play in C for a while, then switch from B natural to B flat, and the flavour of the mode will leap out at you. In order for any mode to sound right, the context has to be firmly established by really knowing which is the key/home note. When you land on that note, there should be a definite finality about it.
PENTATONIC MINOR MAP OF THE FRETBOARD
Knowing the pentatonic minors is only a couple of steps away from knowing everything. In the first A to A of Scales lesson, we saw how the pentatonic minors can be organized into single octave patterns that can be grouped together as matched sets. By becoming totally comfortable with these patterns and the notes they contain, you're also very close to knowing three minor modes, and three majors.
In the first lesson we used the A minor pentatonic. If you know all those scales, then you can easily add the remaining notes to know all the matched A minor and C major modes: A Dorian, Aeolian, Phrygian, C Ionian, Lydian, Mixolydian. I've deliberately left out Locrian because it doesn't fit with my scheme there's always one! Luckily it doesn't sound too great most of the time anyway.
If you know the A minor pentatonic, you already know the C major pentatonic because it's exactly the same five notes just with a different key note. So just use the same matched octaves from the first lesson.
The pentatonics contain five notes, the diatonics 7, So we just need to add in those missing two notes to get our modes.
In the case of the minor pentatonics, the five notes are the 1, 3, 4, 5, and 7: A, C, D, E, G. The Dorian, Aeolian, and Phrygian all have these notes in common. It's the missing 2 and 6 where they differ, and it's these notes that define them and give them their distinctive sounds.
To get the Dorian, you add a major 2 (B) and a major 6 (F#), the Aeolian, a major 2 (B), and a minor 6 (F), and the Phrygian, a minor 2 (Bb and a minor 6 (F).
Below is a matched pair of A minor pentatonic octaves with the extra modal notes added in brackets to make a matched pair of modal octaves.
DORIAN

The major pentatonics use the 1, 2, 3, 5 and 6. In the key of C this would be C, D, E, G and A. The missing modal notes are the 4 and 7, and again, the three major modes, Ionian, Lydian, and Mixolydian all contain the pentatonic notes, and it's the missing 4 and 7 that define their sounds.
The Ionian has a perfect 4 (F) and major 7 (B), the Lydian an augmented 4 (F#) and major 7 (B), and the Mixolydian, a perfect 4 (F) and minor 7 (Bb). Here are a matched pair of C major pentatonics using the same patterns as the A minor, and with the modal notes added in brackets.

It's worth noting that the A Dorian and C Lydian contain the same notes, the A Aeolian and C Ionian, and the A Phrygian and C Mixolydian.
So that's it. If you want to know all your scales/modes, start with the pentatonic minors, which is kind of cool because we tend to start with them anyway.
A final tip: if you ever wanted to play in major keys but found them a little lacking in edge after playing pentatonic/blues scales, try playing in Lydian or Mixolydian first to bridge the gap. These two modes are only one note away from a major scale but have just enough interesting edgy darkness to ease you in to the happy and potentially nursery rhyme sound of the majors.
Hope this was useful. Cheers